RD109 (Hawm Phattalung 72), a Non-glutinous Rice Variety

Abstract

Rice areas in the southern part of Thailand are mainly grown with photoperiod-insensitive rice varieties, which belong to the local varieties and Pathum Thani 1. Though its good grain and outstanding cooking quality of Pathum Thani 1 with soft texture and aroma make a high demand for consumers and millers, but the productive growing areas are limited due to low yield, long growth duration, and diseases and insect pests’ problems. The objective of this study is to develop a photoperiod-insensitive, non-glutinous rice variety with a short growth duration, having good adaptation to the southern rice areas while remaining good cooking quality. A single cross between KKN01041-23-2-1-2 as a female parent and UBN03005-6-3-26-10-49-10 as a male parent was made at Phattalung Rice Research Center in 2014. The promising line named PTL14006-11-1-2-2 outperformed other lines in the same pedigree. During 2015-2023, this line had been under the selections of progenies, observations, the varietal improvement processes of yield trials, as well as evaluating the resistance to major diseases and insect pests, nitrogen response, physical and chemical properties of grain, milling, and cooking quality together with stakeholder acceptance. The Thailand Rice Variety Board agreed to release it in the name of RD109 (Phattalung 72) for the celebrations on the auspicious occasion of His Majesty the King’s 6th Cycle Birthday in 2024. The new variety is a non-photosensitive variety and has a short growth duration of 103 and 112 days from planting to maturity based on germinated seed broadcasting and transplanting methods, respectively. It has an average height of 102 cm, with erect culms and stiff stems. The average yield was 597 kg/rai, approximately 27% higher than that of Pathum Thani 1, while its potential yield is about 1,086 kg/rai. The straw color paddy length is 10.59 mm, 2.59 mm width, and 2.11 mm thick. The length of white-colored brown rice is 7.67 mm, 2.14 mm in width, and 1.89 mm thick, considered as a long and slender shape. Seed dormancy of this variety is four to five weeks. It has very good milling recovery (whole kernel and head 51.80%) with less grain chalkiness. Due to the low amylose content (15.06%) and other involved chemical properties with an aromatic factor of 2.54-3.81 mg/kg of 2AP concentration, this variety has excellent cooking quality. The quality of cooked rice is soft and sticky with aroma. However, it is susceptible to blast, brown planthopper, and bacterial blight. Though, This variety is suitable for growing under irrigated rice areas in southern Thailand, it is not recommended to grow in areas where these mentioned diseases and insects have been prevalent.